Toshiba, which initially held 52.4% of NuFlare, acquired a further 32.3% through a tender offer that ended Thursday, achieving its target of securing more than a two-thirds stake.

Toshiba was aiming to take over NuFlare as the Japanese government pointed to corporate governance issues with dual listings of parents and subsidiaries.

Optical products maker Hoya offered 12,900 yen per NuFlare share or $1.4 billion - a rare unsolicited bid in Japan, topping Toshiba's offer of 11,900 yen.

But Toshiba decided not to accept Hoya's offer, saying the chip equipment unit was core to the group.

(Reporting by Makiko Yamazaki; Editing by Chris Gallagher)